What is the function of FATS (butter, oil...) in baked goods?
Fats assist in carrying the air that is incorporated in the batter during mixing. Fats have a tenderising effect on the cake but it is its ability to carry the air that has more influence on the finished product. Fats also help retain moisture in the finished product. Unsalted butter is recommended for cakes as it produces the best flavour by helping to better release flavours of other ingredients. Leave butter in room temperature to soften before use.